dead duck

A person or thing that is ruined; a GONER, gone goose: Just one more little push and she was a dead duck/ Unless somebody would start this mob to the sugar bowl, I was a dead pigeon(1844+)

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.Copyright (C) 2007 by HarperCollins Publishers.Cite This Source

Idioms and Phrases with dead-duck

dead duck

1.

A person doomed to failure or death; a hopeless case. For example, If they can't find a heart to transplant soon, he's a dead duck.
[ 1940s
]

2.

A useless, worthless, or outmoded person or thing. For example, They didn't interview the outgoing senator; to the press he's a dead duck. Some speculate that this slangy term comes from an old saying, “Never waste powder on a dead duck,” first recorded in 1829.